Block signalling system for railroads



INVENTOR.

March 20, 1956 T. J. JUDGE BLOCK SIGNALLING SYSTEM FOR RAILROADS Filed March 14, 1952 Unite BLOCK SIGNALLING SYSTEM FOR RAILROADS Patent Thomas J. Judge, Rochester, N. L, assignor to General Railway Signal Company, Rochester, N. Y. Application March 14, 1952, Serial No. 276,647 I 4 Claims. c1. 246-33) erally picked up upon the entrance of a train into the track section governed by the associated signal. This of course requires a track relay at the intermediate signal location for each track section adjoining that location. The provision of track relays in this manner requires additional track circuits because it is necessary to add cut sections whereby there will always be a track relay at each double intermediate signal location for each of the signals.

According to the present invention, the installation of cut sections to provide the above allocation of track relays is not required as both stick relays at a double intermediate signal location are governed by the same track relay. Thus it is necessary to have but one track relay at a double intermediate location as compared to the usual requirement of two relays. This is because the stick circuits are so organized that the stick relay for one direction of 'traific is picked up upon acceptance of the associated signal, while the stick relay for the other direction of traflic is picked up when a train enters the track section in approach to the associated signal. In this way control in each case is by the same track circuit, and thus the track circuit chosen for the control of the stick relays is the circuit having a track relay at the intermediate signal location, the other track circuit adjoining the signal location being permitted to have its track fed at the signal location.

An object of the present invention is therefore to reduce to a minimum the number of track circuits required in an APB signalling system by controlling the stick relays at a double intermediate signal location by the same track relay.

Other objects, purposes, and characteristic features of the present invention will be in part obvious from the acpanying drawings, and in part pointed out as the description of the invention progresses.

In describing the invention in detail reference is made to the accompanying drawing in which similar letter reference characters are used to designate parts having similar features and functions, with preceding numerals being employed to indicate particular locations or devices with which the respective parts are associated.

For the purpose of simplifying the illustration and explanation, the various parts and circuits constituting the embodiment of the invention have been shown diagrammatically and certain conventional illustrations have been employed, the drawing having been made more with the purpose in mind of making it easy to understand the principles and mode of operation, than the idea of illustrating the specific construction and arrangement of parts,

that would be employed in practice. Thus, the relays and contacts are illustrated in a conventional manner and symbols are used to indicate the connections to the terminals of batteries, or other sourcesjof electric current, instead of showing all of thewir ing connections to these ter minals. The symbols and are employed to indicate the positive and negative terminals respectively of suitable'batteries,.for;othersourcesof direct current. In

the drawings, equipment is locatedat several different points, along the trackway .and.it is assumed that suitable sources of direct current, as represented by the symbols, are provided at each of these different spaced points as required. I i v The 'trackway illustratedjs assumed to be a portion of trackway. constituting a-,block extending between two passing'sidingsof a single '-track,railroad-,the block being dividedinto respective track sections including the track sections 21 and 4T which areillustrated as adjoining an intermediate signal location wherein signal 4 is provided for governing eastbound traffic and signal 5 is provided for governing westbound trafiic. It is assumed that similardouble intermediate signal locations are provided at the opposite'ends of the track sections 2T and 41, and i thus the signall is provided for-governing eastbound trafiic-into the track sctionfZT, and signal 6 is provided for 'governingea stbound tratfic leaving the track section 4T. Similarly the-signal 3 is provided for governing westbound trafl'ic leaving track. section 2T and signal 7 is I provided for governing westbound trafiic entering track section 4T.

Although the signalslemployed c an be of any conventional type,-for this emboidmentof the present invention, the signalsare consider'ed to be,;of the searchlight type such as is disclosed, for examplepin the patent of O. S Field, No. 2,239,316, dated April 22, 1941.

-.Each signal-has associated therewith a yellow-green repeater relay YGP which has slowdrop away characteristics as is the usual practicefor repeater relays of this type. These relays arernormally, energized because of their associated signals beingnormally clear.

Line circuitsare shown, for-thecontrol of the signals,

theseline circuits beingof the three-wire type, although it is to be understood-thatline circuits of the two-Wire type maybe employed in accordance with the requirements of practice.

Directional stickrelays 38, 48, 5S; and 68 are illustrated as beingassociated, with: the respective signals 3', 4, 5, and 6. 1

Having thus described the system apparatus, more detailed consideration will hereinafter begiven as to the specific ,organizations'when consideringvarious typical conditions of operation of the system.

I I Operation 7' The conditions of the apparatus illustrated correspond to the conditions of the system when there is no train present in theblock. Thus the respective signal mechanisms are energized with a polarity to cause actuation of the signals to clear positions, the signals being dark in accordance with the provision of approach lighting. Thus the signal 2 is energized over the line circuit from the next signal in advance bya circuit extending from including front contact 20 of relay 4YGP, line wire 21, front contact 22 of relay:2TR, back contact 23 of relay 3S, winding of signal 2, common wire 24, and frontcontact 25.0f relay 4YGP, to Signal 4 similarly has its mechanism energized with a'positive polarity by a circuit including front contact 26 of relay 6YGP, line wire 27,

front contact 280i relay 4TR, back contact 29 of relay .Paite ea -Mar.; 20,1956

mechanism of signal 5 in its left-hand position and front contact 45 of relay 4TR. With this relay picked up, the stick relay SS is dropped away because of its circuit being opened at back contact 58 of relay SYGP and at back contact 57 of relay 4TR. The dropping away of relay SYGP applies normal polarity to the line circuit for the control of signal 7 by the energization of a circuit which has been described.

As the Westbound train progresses further so that signal 3 becomes energized with reverse polarity, the relay 3YGP is picked up upon the closure of front contact 6 of relay ZTR, and the picking up of this relay causes the dropping away of the stick relay 3S and applies normal polarity to the line circuit for the control of signal 5 to operate the mechanism of that signal to its clear position.

Having thus described the apparatus involved at specific intermediate signal locations as one embodiment of the present invention, it is to be understood that the principles of the invention can be applied to other track layouts and systems using other types of signals and modified forms of signal control and track circuits, and that various modifications, adaptations, and alterations may be applied to the specific form of the invention herein disclosed according to the requirements of practice except as limited by the appended claims.

What I claim is:

1. In an absolute permissive block signalling system, apparatus at a double intermediate signal location com prising in combination, signals at said location for governing traffic in both directions, a track circuit adjoining said location having a track relay, a signal repeater relay for each or" the signals, circuit means for energizing said signal repeater relay when its associated signal is clear and for deenergizing said signal repeater relay when the associated signal is put to stop, a directional stick relay for each of the signals, pickup circuit means for energizing each of said directional stick relays through a back contact of said track relay and through a front contact of said signal repeater relay for the associated signal, whereby the stick relay for one signal is picked up when a train accepts the signal and the stick relay for the signal for the opposite direction of trafiic is picked up when a train is on the track circuit in approach to the signal.

2. In an absolute permissive block signalling system, apparatus at a double intermediate signal location comprising in combination, a track circuit adjoining said location, said track circuit having a track relay, a signal at said location for governing trafiic in each direction, a slow acting signal clear repeater relay for each signal, directional stick relays for the respective signals for governing the energization of line wires extending to signals in the rear, circuit means for energizing said signal repeater relay in accordance with the associated signal being clear, said circuit means being efiective to deenergize said signal repeater relay when the associated signal is put to stop, a directional stick relay for each of the signals pickup circuit means for energizing each of said stick relays in response to the dropping away of said track relay provided that said signal repeater relay for the associated signal is picked up, stick circuit means for maintaining each of said stick relays energized for a time subsequent to the dropping away of said signal repeater relay for the associated signal, and line circuit control means energized in response to the energization of said stick relay for governing the next signal in the rear.

3. In an absolute permissive block signalling system, apparatus at a double intermediate signal location comprising in combination, signals at said location for governing both directions of trafiic, a track circuit adjoining said location for the approach to one of said signals, a track relay responsible to energization of said track circuit, a slow acting signal clear repeater relay for each signal, directional stick relays for the respective signals for governing the energization of circuits for the control of the respective signals in the rear, circuit means for energizing said signal repeater relay in accordance with the associated signal being cleared, said circuit means being effective to deenergize said signal repeater relay when the associated signal is put to stop, pickup circuit means for energizing each of said stick relays in response to the dropping away of said track relay provided that said signal repeater relay for the associated signal is energized and provided that said stick relay for the opposing signal is dropped away, stick circuit means for maintaining each of said stick relays energized for a time subsequent to the dropping away of said signal repeater relay for the associated signal, and line circuit means energized in response to the energization of said stick relay for governing the next signal in the rear.

4. In an absolute permissive block signalling system, apparatus at a double intermediate signal location comprising in combination, a signal at said location for each direction of trafiic, a track circuit adjoining said location in approach to a given one of said signals, said track circuit including a track relay, a slow acting signal clear repeater relay for each signal, directional stick relays for the respective signals for governing the energization of line circuits extending to respective signals in the rear, circuit means for energizing said signal repeater relay when the associated signal is clear and for deenergizing said signal repeater relay when the associated signal is put to stop, pickup circuit means for energizing each of said stick relays in response to the dropping away of said track relay provided that said signal repeater relay for the associated signal is picked up, said pickup circuit means including back contacts of the stick and signal repeater relays for the opposing signal, stick circuit means for maintaining each of said stick relays energized for a time after said track relay is picked up, and line circuit means associated with each signal and extending to the next signal in the rear having its energization governed by said stick relay for the associated signal.

References Cited in the tile of this patent UNITED STATES PATENTS 1,910,360 Pelikan et al. May 23, 1933 2,096,939 Phinney Oct. 26, 1937 2,364,840 Zane et al. Dec. 12, 1944 2,588,836 Holden Mar. 11, 1952 

